1. Field of the Invention
The present invention relates to a method of producing an ultrafine crystalline TiN/TiB2 composite cermet. More particularly, the present invention pertains to a method of producing an ultrafine TiN/TiB2 cermet, in which titanium nitride (TiN)/titanium boride (TiB2)/stainless steel composite nanopowder is produced through a reaction milling process using titanium (Ti), boron nitride (BN), and stainless steel powders as raw material powders and the resulting composite nanopowder is liquid-phase sintered.
2. Description of the Related Art
Titanium nitride is extensively used for cutting tools and wear-resistant parts due to its excellent wear resistance and high temperature strength. Since titanium boride has excellent high temperature oxidation and a very high elastic coefficient, it is not deformed at high temperatures, thus being used for bulletproof materials, cutting tools, and wear-resistant materials (Korean Patent Registration No. 456797).
In accordance with the recent emphasis on studies conducted to significantly improve the physical properties of cutting tools and high temperature wear-resistant materials, miniaturization is conducted, so that the size of a hard phase crystal is 1 μm or less, and two or more hard phases are dispersed to achieve combination thereof. Particularly, it is necessary to develop an ultrafine crystalline composite cermet in order to develop cutting tools for high precision processing, demand for which has recently increased.
According to known methods of producing an ultrafine crystalline composite cermet, a composite nanopowder having a crystalline size of 100 nm or less is produced using a gas phase method or a liquid phase method, and is then sintered (Korean Patent Registration No. 494976). However, the gas phase method and the liquid phase method are problematic in that the production cost is very high, productivity is low, and there is a high possibility of oxidation in the case of exposure to air, thus they are unsuitable for the mass production of raw material powder for the cermet.